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Infectious Amphibian Diseases

Photo: ranavirus.org

Photo: Alan Cressler

What are they?

Ranaviruses and amphibian chytrid fungus are diseases that infect amphibians, and are responsible for large-scale die-offs of multiple species in the Pacific Northwest. Ranaviruses are a group of related viruses infecting cold-blooded animals like turtles, fish, and particularly amphibians. They mostly kill amphibians during the larval stages, so species without larval stages are less affected. Amphibian chytrid fungus causes the disease ‘amphibian chytridiomycosis’ which interferes with the amphibian’s ability to breathe and to take up water through their skin.

Are they here yet?

Yes. Certain amphibian ranaviruses are present across Washington, and amphibian chytrid fungus is also present in amphibian populations in Washington.

Why should I care?

While neither ranaviruses nor amphibian chytrid fungus are known to be transmittable to warm-blooded animals (including humans and other mammals), they pose a significant risk to the state’s amphibians. Amphibian chytrid fungus is capable of infecting most species of amphibians. Certain types of ranaviruses have the potential to kill upwards of 90% of a population of amphibians. Several species of concern are thus threatened by both ranaviruses and amphibian chytrid fungus, which have the potential to rapidly wipe them out. While ranaviruses with the potential to kill salmonid fish species are not yet present in Washington, if introduced they could devastate salmon populations.

What should I do if I find it?

How can we stop them?

To stop the spread of amphibian diseases, do not release cold-blooded animals like amphibians, reptiles or fish into the wild. Thoroughly clean and dry all wet or muddy footwear before travelling elsewhere, as amphibian chytrid funguses can be transported in mud or water.

What are their characteristics?

Amphibians infected with a ranavirus may hemorrhage in small bloody spots or patches on their underbellies.

Amphibian chytrid fungus may make an amphibian’s skin slough off or appear bloodshot.

Both ranaviruses and amphibian chytrid fungus can cause lethargy or odd behaviors in amphibians, such as erratic or weakened motion.